The invention relates to a grid element for an inhaler which can be arranged in an air duct between a mouthpiece and a capsule chamber of the inhaler, it being possible for turbulence to be generated by means of the grid element in an airflow passing through the air duct.
In the prior art, several principles according to which inhalers operate are known. The present invention relates to a grid element for inhalers for the inhalation of pulverulent pharmaceutical products from capsules. Such inhalers are also referred to as Bernoulli inhalers and are marketed for example under the name HandiHaler. In this case, the pulverulent active ingredient is stored in a capsule. These capsules are conventionally produced from hard gelatine and consist of two cylindrical parts, the ends of which are in the form of hemispheres. Document DE 198 35 346 A1 discloses for example such a capsule.
Such a capsule is introduced into a generally cylindrical capsule chamber of the inhaler. Said capsule chamber comprises an air inlet at one of the axial ends thereof, and an air outlet duct at another axial end, which air outlet duct extends as far as the mouthpiece. Furthermore, the capsule chamber is dimensioned in such a way that the length and width thereof are greater than the dimensions of the capsule. However, the axial longitudinal axis of the capsule is still arranged substantially in parallel with an axial longitudinal axis of the capsule chamber.
Prior to an inhalation, the capsule must firstly be opened. For this purpose, the inhaler comprises a piercing or cutting device. Said piercing device comprises two needles which are at a distance from one another along an axis which extends in parallel with the axial longitudinal axis of the capsule chamber. The needles are pressed against the capsule by means of an actuation button, as a result of which two openings are produced in the longitudinal outer surface of the capsule. Some capsules comprise corresponding taperings in material at the piercing points.
If air is now sucked through the mouthpiece, an airflow is produced in the capsule chamber from the air inlet to the air outlet duct. By means of the airflow flowing past the openings, a negative pressure is generated in front of the capsule openings with respect to the inside of the capsule, so that the powder which is located in the capsule is carried away by the airflow and atomised in the process. In addition, the capsule vibrates through the airflow predominantly along the axial longitudinal axis. Due to the already-mentioned dimensioning of the capsule chamber, the capsule can vibrate both vertically and horizontally.
Such inhalers are disclosed for example in documents DE 39 27 170 A1, DE 33 45 722 A1 and DE 43 18 455 A1.
In the inhalers mentioned at the outset, a grid or a filter respectively is conventionally arranged between the mouthpiece and the capsule chamber. This grid is used to generate turbulence in the airflow which passes through the air outlet duct. This turbulence assists with deaglommeration of the inhalation powder, as a result of which the active ingredients are better distributed in the aerosol to be breathed in and thus can be better absorbed by the lungs. In addition, such a grid is intended to filter undesirable particles from the capsule chamber out of the inhalation path. Undesirable particles of this type are for example plastics material particles which are produced by means of the abrasion of the needles for opening the capsule on the housing or fragments of the capsule which are produced when opening the capsule. An additional function of the grid is to spatially limit the movement of the capsule in the capsule chamber. The ability of the capsule to move must be limited in such a way that, although it can vibrate both vertically and horizontally in the capsule chamber, in this respect, it still remains oriented substantially in parallel with the axis of the chamber. So that the grid provides a spatial delimitation of this type, it must have a shape which is appropriate for insertion in the inhaler. Such a grid is typically produced by overmoulding a plastics material frame on a metal grid, which frame is then inserted in the inhaler. Such grids are thus expensive and elaborate to produce.
It is thus an object of the invention to provide a grid element for an inhaler which is simple and cost-effective to produce. It is also an object of the present invention to provide an inhaler having such a grid element.